#region MigraDoc - Creating Documents on the Fly
//
// Authors:
//   Stefan Lange
//   Klaus Potzesny
//   David Stephensen
//
// Copyright (c) 2001-2019 empira Software GmbH, Cologne Area (Germany)
//
// http://www.pdfsharp.com
// http://www.migradoc.com
// http://sourceforge.net/projects/pdfsharp
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
// DEALINGS IN THE SOFTWARE.
#endregion

using System;
using MigraDoc.DocumentObjectModel.Internals;

namespace MigraDoc.DocumentObjectModel
{
    /// <summary>
    /// A TabStops collection represents all TabStop objects in a paragraph.
    /// </summary>
    public class TabStops : DocumentObjectCollection
    {
        /// <summary>
        /// Specifies the minimal spacing between two TabStop positions.
        /// </summary>
        public static readonly double TabStopPrecision = 1.5;

        /// <summary>
        /// Initializes a new instance of the TabStops class.
        /// </summary>
        public TabStops()
        { }

        /// <summary>
        /// Initializes a new instance of the TabStops class with the specified parent.
        /// </summary>
        internal TabStops(DocumentObject parent) : base(parent) { }

        #region Methods
        /// <summary>
        /// Creates a deep copy of this object.
        /// </summary>
        public new TabStops Clone()
        {
            return (TabStops)DeepCopy();
        }

        /// <summary>
        /// Gets a TabStop by its index.
        /// </summary>
        public new TabStop this[int index]
        {
            get { return base[index] as TabStop; }
        }

        /// <summary>
        /// Gets a TabStop by its position.
        /// Note that also Removed TabStops are taken into account.
        /// </summary>
        public TabStop GetTabStopAt(Unit position)
        {
            int count = Count;
            for (int index = 0; index < count; index++)
            {
                TabStop tabStop = (TabStop)this[index];
                if (Math.Abs(tabStop.Position.Point - position.Point) < TabStopPrecision)
                    return tabStop;
            }
            return null;
        }

        /// <summary>
        /// Returns whether a TabStop exists at the given position.
        /// Note that also Removed TabStops are taken into account
        /// </summary>
        public bool TabStopExists(Unit position)
        {
            return GetTabStopAt(position) != null;
        }

        /// <summary>
        /// Adds a TabStop object to the collection. If a TabStop with the same position
        /// already exists, it is replaced by the new TabStop.
        /// </summary>
        public TabStop AddTabStop(TabStop tabStop)
        {
            if (tabStop == null)
                throw new ArgumentNullException("tabStop");

            if (TabStopExists(tabStop.Position))
            {
                int index = IndexOf(GetTabStopAt(tabStop.Position));
                RemoveObjectAt(index);
                InsertObject(index, tabStop);
            }
            else
            {
                int count = Count;
                for (int index = 0; index < count; index++)
                {
                    if (tabStop.Position.Point < ((TabStop)this[index]).Position.Point)
                    {
                        InsertObject(index, tabStop);
                        return tabStop;
                    }
                }
                Add(tabStop);
            }
            return tabStop;
        }

        /// <summary>
        /// Adds a TabStop object at the specified position to the collection. If a TabStop with the
        /// same position already exists, it is replaced by the new TabStop.
        /// </summary>
        public TabStop AddTabStop(Unit position)
        {
            if (TabStopExists(position))
                return GetTabStopAt(position);

            TabStop tab = new TabStop(position);
            return AddTabStop(tab);
        }

        /// <summary>
        /// Adds a TabStop object to the collection and sets its alignment and leader.
        /// </summary>
        public TabStop AddTabStop(Unit position, TabAlignment alignment, TabLeader leader)
        {
            TabStop tab = AddTabStop(position);
            tab.Alignment = alignment;
            tab.Leader = leader;
            return tab;
        }

        /// <summary>
        /// Adds a TabStop object to the collection and sets its leader.
        /// </summary>
        public TabStop AddTabStop(Unit position, TabLeader leader)
        {
            TabStop tab = AddTabStop(position);
            tab.Leader = leader;
            return tab;
        }

        /// <summary>
        /// Adds a TabStop object to the collection and sets its alignment.
        /// </summary>
        public TabStop AddTabStop(Unit position, TabAlignment alignment)
        {
            TabStop tab = AddTabStop(position);
            tab.Alignment = alignment;
            return tab;
        }

        /// <summary>
        /// Adds a TabStop object to the collection marked to remove the tab stop at
        /// the given position.
        /// </summary>
        public void RemoveTabStop(Unit position)
        {
            TabStop tab = AddTabStop(position);
            tab.AddTab = false;
        }

        /// <summary>
        /// Clears all TabStop objects from the collection. Additionally 'TabStops = null'
        /// is written to the DDL stream when serialized.
        /// </summary>
        public void ClearAll()
        {
            Clear();
            _fClearAll = true;
        }
        #endregion

        #region Properties
        /// <summary>
        /// Gets the information if the collection is marked as cleared. Additionally 'TabStops = null'
        /// is written to the DDL stream when serialized.
        /// </summary>
        public bool TabsCleared
        {
            get { return _fClearAll; }
        }
        internal bool _fClearAll = false;
        #endregion

        #region Internal
        /// <summary>
        /// Converts TabStops into DDL.
        /// </summary>
        internal override void Serialize(Serializer serializer)
        {
            if (_fClearAll)
                serializer.WriteLine("TabStops = null");

            int count = Count;
            for (int index = 0; index < count; index++)
            {
                TabStop tabstop = this[index];
                tabstop.Serialize(serializer);
            }
        }

        /// <summary>
        /// Determines whether this instance is null (not set).
        /// </summary>
        public override bool IsNull()
        {
            // Only non empty and not cleared tabstops (TabStops = null) are null.
            if (base.IsNull())
                return !_fClearAll;
            return false;
        }

        /// <summary>
        /// Returns the meta object of this instance.
        /// </summary>
        internal override Meta Meta
        {
            get { return _meta ?? (_meta = new Meta(typeof(TabStops))); }
        }
        static Meta _meta;
        #endregion
    }
}
